Habitat suitability mapping of the Indian giant flying squirrel (Petaurista philippensis Elliot, 1839) in India with ensemble modeling

Abstract

Flying squirrels are one of the least studied mammalian taxa in South Asia as well as in India owing to their nocturnal, arboreal and cryptic nature. We applied ensemble species distribution modeling using BIOMOD2 (ver 1.0) R-package to predict the suitable habitat of the Indian giant flying squirrel (Petaurista philippensis, Elliot 1839) in Indian biogeographic regions and states, and to identify the physical variables that define its fundamental niche. A subset of least correlated variables from bioclimatic (mean diurnal temperature range, temperature isothermality, precipitation of wettest month, precipitation of driest month and precipitation of warmest quarter, and precipitation of coldest quarter), topographic (elevation), water-related (distance to major water streams), and vegetation-related (NDVI, and vegetation height) data sets were used in the modeling. The accuracy of the final ensemble habitat suitability model was characterized by the receiver operating characteristic curve (ROC) and true skill statistic (TSS). In India, a total of highly suitable habitat for the species was estimated to be 66,743 sq. km, varying between states and biogeographic regions. Final model revealed that predictive suitable habitat of the species was limited primarily to the southern peninsula, including the Western Ghats, the Deccan peninsula, and the semi-arid region, and to a lesser extent, the coastal areas of the Kerala state. At the state level, majority of suitable habitat for the species estimated in Kerala followed by Karnataka, Tamil Nadu, Gujarat, Maharashtra, Rajasthan, and Madhya Pradesh. Climatic factors, particularly temperature and precipitation, have been identified as major determinants of Indian giant flying squirrel's potential habitat. We suggest that several new areas in the modeling that showed suitable habitat for the species necessitate immediate attention to validate species occurrence through field work. Extensive further studies on the species could also provide a detailed insight into the species' dispersion, colonization and the effect of future climate change in the Indian subcontinent.